I have a crack on one of the solution tanks on my Hagie 2100.  The crack is down in one of the corners and I can only get to it from the outside.  The crack is about an inch, inch and half long.  Not very big....yet.

I tried to seal it up with some Jb Weld water stuff.  that lasted about 10  minutes.  Then I tried some waterproof adheasive caulk, same deal.  At the time I was looking for a temporary fix.  Now I would like to find something more permanent other than a brand new tank ($1200). 

I have heard about some sort of welding that can be done to poly tanks but know of no one who has actually done it or had it done.  How bout you guys?

Any help sure would be appreciated.  TIA